15+ Facts about Koko, the gorilla who knew sign language
Koko, the famous gorilla, transformed how scientists understood her species. Her remarkable intelligence went far beyond what anyone imagined—she mastered thousands of sign language words, expressed herself through painting, played musical instruments, showed deep empathy, and amazed everyone with her unique abilities. Keep reading to uncover the story behind what made Koko truly extraordinary.
She Was Able To Express Empathy
Empathy is a sophisticated emotional skill that not all mammals seem to possess. One of Koko’s most extraordinary traits was her genuine capacity for compassion.
In the movie Tea with Mussolini, there’s a poignant scene where a young boy is separated from his family. Watching this, Koko’s eyes filled with tears as she signed words like “sad,” “cry,” “trouble,” and “mother,” demonstrating her profound emotional insight and remarkable ability to empathize with others.
She Could Play The Recorder
Among Koko’s remarkable achievements was mastering the recorder—a musical instrument many believed was too difficult for gorillas to handle.
Her proficiency with the recorder highlighted not just her intelligence but also her exceptional breath control. Because wind instruments require careful regulation of breathing, Koko’s skill demonstrated an impressive combination of physical coordination and cognitive awareness.
She Could Paint And Judge Paintings
Koko and her male companion, Michael, both showed a surprising talent for painting. Although much of their art leaned toward the abstract, it wasn’t just aimless brushwork—in many cases, their pieces were inspired by things they saw around them.
What truly set their creations apart was their capacity to evaluate their own work. If they didn’t like a painting, they would sign “toilet” to indicate their displeasure. Some of their most impressive artworks can still be viewed today on the Gorilla Foundation’s website.
Koko “Adopted” A Kitten
Koko had a special fondness for kittens and loved hearing stories like The Three Little Kittens and Puss ‘n’ Boots. When she asked for a pet kitten, her caretakers initially gave her a stuffed toy, but Koko signed “sad,” making it clear she wanted a real one. Recognizing her feelings, they let her pick a kitten from a litter. She named her new furry friend All Ball and nurtured it with the same gentle care she would show to her own baby.
She Made Up Phrases And Sounds
Koko went beyond just learning sign language—she also crafted her own unique ways to communicate. Alongside the usual gorilla sounds like grunts and purrs, she invented distinct vocalizations all her own.
When encountering something without a specific sign, Koko cleverly combined existing signs to express the concept. For instance, lacking a sign for “ring,” she used the signs for “finger” and “bracelet” together to get the idea across. This showed her impressive talent for understanding language and adapting it in creative ways.
Her First Words Were Related To Eating
Getting enough to eat and drink is one of the biggest things on an animal’s mind, so it’s not much of a surprise that all of Koko’s first words were related to diet.
The first words that Koko was able to sign successfully were “more,” “food,” and “drink.” Many pets communicate these desires to their owners all the time in their own ways. Through interspecies communication, animals can more precisely convey their needs to their caretaker.
She Understood Mortality
One thing that sets humans apart from many other mammals is our awareness of mortality. Koko proved that she also knew that creatures would cease to exist. When shown a skeleton, Koko was able to indicate through sign language that it was dead.
The gorilla was then asked where the skeleton would go, to which she signed, “A comfortable hole.” Koko even gave a kiss goodbye, showing that she understands that the deceased are gone.
Penny Was Koko’s Caretaker For Decades
Koko was just one year old when researcher Francine “Penny” Patterson took the gorilla under her wing. Penny approached the San Francisco Zoo to ask them to use Koko for a Ph.D. thesis.
The zoo agreed under the stipulation that Penny commit to caring for Koko for at least four years. Penny ended up remaining Koko’s caretaker for the remainder of the gorilla’s life! Penny was able to teach Koko around 2,000 words over the decades.
Koko And Her Companion Signed To One Another
Koko and her companion Michael didn’t just sign for researchers. They also communicated with one another through sign language. One breakthrough moment was when Michael relayed his memory of his mother’s death to Koko.
Michael’s mother was killed by poachers, so his ability to recall the event was a huge stride in the fight to prevent illegal gorilla hunting. The Gorilla Foundation takes in orphaned gorillas and helps protect the species through education and research.
Robin Williams Helped Koko Mourn Her Companion
One thing that illustrated Koko’s advanced emotional capacity was her ability to grieve the loss of others. When her companion Michael passed, the gorilla experienced loss of appetite and she even stopped smiling.
Comedian Robin Williams visited Koko around this time and his lighthearted presence impacted Koko. He got her to laugh and play games again, which was a sign that her sadness could at least be kept at bay with the help of the friendly comedian.
Roses Were One Of Koko’s Favorite Foods
Gorillas spend about half of their time foraging for food, so it was important that Koko get to experience this part of life. The Gorilla Foundation would create a sort of foraging game for Koko so she still had to work for the food they gave her.
She received seven meals each day, and each meal was a pound of plant-based food! One of Koko’s favorite foods was roses, along with carnations, plantains, and berries.
Her Communication Skills Rivaled That Of A Human Toddler
Koko’s communication skills have been compared to that of a three-year-old human. Likewise, the gorilla learned most of her vocabulary between the ages of two and five.
Though she wasn’t able to grasp grammar and syntax, Koko did understand thousands of words that made it possible to have a back and forth conversation with her. She was also able to help researchers teach sign language to her male counterpart, Michael, who developed a 600-word vocabulary.
She Helped Mr. Rogers Take Off His Shoes
Koko genuinely enjoyed watching TV. Some of her favorite movies were Free Willy, Doctor Doolittle, Maid in Manhattan, and Pretty Woman. She also loved Mister Rogers’ Neighborhood.
Koko was such a fan that when she met Mr. Rogers, she recognized him right away. The gorilla even helped Mr. Rogers take off his shoes because she remembered him doing that in the show! Moments like these showed that Koko was really absorbing all that she observed.
She Had A Safety Blanket
Part of what made Koko such a brilliant animal was her natural curiosity. The gorilla loved to play and was very active. Investigating things is how Koko learned more about them, even as a child.
Though Koko was very interested in learning more about the world around her, she was also naturally timid. When she went to a new location, Koko had to have her security blanket around as a sense of safety and comfort.
She Passed The Mirror Test
Another way that Koko stood out was her ability to pass the mirror test. The test consists of putting an animal under anesthesia and marking them with paint or a sticker.
The mark goes on a spot that they wouldn’t be able to see without the help of a mirror. When the animal wakes up, they see the mark in the mirror. If they go to touch it on themselves, then it indicates a higher level of self-awareness.
Koko’s Fans Sent Her Birthday Cards
One of the aims of The Gorilla Foundation is to spread awareness of these animals. In doing so, they create more empathy toward gorillas that encourages others to take care of the incredible species.
Koko was a fundamental part of this mission since her advanced skillset made her more relatable. The gorilla’s supporters were such big fans that they would sometimes send in cards and presents on Koko’s birthday! Knowing that Koko could feel complex emotions made the offerings all the more special.
She Could Reference Objects That Weren’t Around
While animals can sometimes learn to recognize certain words, it’s often in reference to something nearby. Something that made Koko stand out was her ability to reference things that weren’t even around her.
This skill is called displacement and it isn’t common among animals. Koko’s ability to call to mind things that weren’t around greatly expanded the breadth of conversations that she could have. It was also an example of her memory and communication working together.
Her Name Means “Fireworks Child”
Researchers didn’t just come up with the name Koko because it was cute. Koko’s full name is actually Hanabiko, which means “fireworks child” in Japanese. Koko was born on the 4th of July, a holiday that is known for its fireworks.
Her birth took place in 1971 at the San Francisco Zoo, where her parents Jacqueline and Bwana lived. Koko also had two brothers through which she has nieces and nephews who still reside in zoos around the US.
She Wanted To Be A Mother
Koko loved to treat visiting kittens like they were her own. She would even sign “baby” while holding the kitten. This made her caretaker, Penny, well-aware that Koko wanted to be a mother.
Though Koko grew up with fellow gorilla Michael, they never became more than friends. Koko did mate with a gorilla named Ndume, but she miscarried. Penny later told ABC News, “I think that’s one of Koko’s deepest regrets is not having a baby.”
Koko Referred To Herself As “Queen”
Koko got to such an advanced level that she could use sign language to not only describe the world around her, but also herself. One of the first words Koko ever used in reference to herself was “queen.”
Her lifelong caretaker and teacher, Penny, surmised that Koko knew how unique she was due to all of the attention she got. Koko was too smart to not notice what an impact she was making, even if she didn’t exactly know how.
